The OLED (Organic Light-Emitting Diode) display, which is also named as the Organic light emitting display, is a new flat panel display device. Because it possesses advantages of simple manufacture process, low cost, low power consumption, high light emitting brightness, wide operating temperature range, thin volume, fast response speed, and being easy to achieve the color display and the large screen display, and being easy to achieve the match with the integrated circuit driver, and being easy to achieve the flexible display. Therefore, it has the broad application prospects.
The OLED display utilizes the organic light emitting diode for light emission. Thus, it is extremely important to improve the efficiency and lifetime of the organic light emitting diode. Now, the organic light emitting diode has already made considerable progress. With the fluorescence phosphorescence hybrid, the white light element with the simple structure and high efficiency can be obtained. The efficiency of such fluorescence phosphorescence hybrid element significantly relies on the efficiency of the fluorescence. Therefore, it still has vital significant meaning to develop the high efficiency fluorescence material.
In comparison with polymer, the small molecule light emitting molecule has the simple steps, the stable structure and can be purified, and then the higher element efficiency can be obtained for the possible commercial application. The method of manufacturing multiple layer element by implementing evaporation or solution process with small molecule has already drawn the great attention and the great progress has been made. However, the traditional organic fluorescence material only can utilize 25% of singlet excitons. Thus, there is extreme big restriction to the efficiency of the element. Recently, the Japanese Adachi research group utilizes the thermally activated delayed fluorescence mechanism to make the exciton availability of all organic material reach up to 100%, and the organic fluorescence element efficiency progresses significantly. Nevertheless, there is few for such kind of materials. Therefore, the type expansion for such kind of material has the significant meaning for the application in the future. For now, the organic small molecule light emitting material of simple structure, and possessing well performance and satisfying the commercialization requirement is still so limited. It is still profound to develop the light emitting material of low cost and excellent efficiency.